Potential Ecological Risk of Swamps Sediments in Illegal Refineries Sites: A Case Study of Isoko South, Delta State, Nigeria

Abstract

This study was carried to determine the level of heavy metals toxicity in swampy forest of Isoko South, Delta State, Nigeria. Sediments samples were collected from nine spatial points, within the swampy forest of Enwhe community of Delta State, Nigeria. The study area contained clusters of illegal crude oil refineries, before they were destroyed by the Nigeria military, during the first quarter of 2020. A total area of 1 km2 of the swampy environment was covered in this study. Six toxic heavy metals (Cu, Zn, Cr, Cd, Pb, and Ni) contents, in the sediments were determined in accordance to international approved standards. The results revealed that the activities of the illegal refineries located in the study area, significantly increased the heavy metals toxicity in the sediments. When compared with the results obtained from a reference point, the concentrations of the heavy metals were significantly higher, across the study area. Within the study area, spatial points B and D sediments contained the highest heavy metals concentrations. In addition, the study revealed that contamination factor of the sediments ranged between moderate and high degree of heavy metals contamination. This portrayed the potential ecological risks of the illegal refineries activities, to the environment of the region. Therefore, if these illegal refineries activities are allowed to continue unabated, they will cause a serious ecological risk to the Niger Delta region ecosystems.

Effects of Illegal Refineries On Aquatic Life in The Niger Delta, Nigeria: A Review

“…This could be attributed to the volume of petroleum products received by these points during the crude oil refining process. Similar results on the effects of petroleum products on the heavy metals concentrations in soils samples were reported by Iwegbue (2011) and Akpomrere and Uguru (2020). According to the Iwegbue (2011), the Ni, Cd and Zn concentration of crude oil impacted soils increased from 7.0 to 31 mg/kg, 0.02 to 1.12 mg/kg and 23 to 29.3 mg/kg respectively.…”

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“…Concentrations, after soils samples were contaminated with petroleum products. Heavy metals are those metals with high relative density (greater than 5g/cm 3 ), when compared with water (Fergusson, 1990;Akpomrere and Uguru, 2020). Heavy metals are persistence and nonbiodegradable; therefore, they continue to accumulate in the ecosystems.…”

Environmental Impact Assessment of Vehicular Traffic along Major Roads in Delta State of Nigeria, Using Contamination and Enrichment Factors

“…Contamination Factor is the ratio of the heavy metal concentration at the sampled site to the heavy metal concentration at the control point; and it is calculated with the expression given in Equation 3 [31].…”